Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

mdoc: order prologue macros consistently by Dd/Dt/Os

Although groff_mdoc(7) gives another impression, this is the ordering
most widely used and also required by mdocml/mandoc.

Reviewed by: ru
Approved by: philip, ed (mentors)

Catch up with the VFS_VPTOFH(9) -> VOP_VPTOFH(9) repocopy that happened
almost three years ago in r166794.

PR: 140989
Submitted by: Lachlan Kang
MFC after: 1 week

The .Fn macro.

Mdoc Janitor:

* Use 'manual' instead of 'man' for consistency.

Some mdoc(7) fixes:

Nuke incorrect usage of .Ar; replace it with .Vt, .Va or .Fa appropriately.
The .Ar mdoc(7) specifier should only be used when displaying command line
arguments.

Approved by: des (mentor)

Uniformly refer to a file system as "file system".

Approved by: re

More file system > filesystem

mdoc(7) police: Use the new .In macro for #include statements.

Removed whitespace at end-of-line; no content changes. I simply did
cd src/share; find man[1-9] -type f|xargs perl -pi -e 's/[ \t]+$//'

BTW, what editors are the culprits? I'm using vim and it shows
me whitespace at EOL in troff files with a thick blue block...

Reviewed by: Silence from cvs diff -b
MFC after: 7 days

mdoc(7) police: remove extraneous .Pp before and/or after .Sh.

Fixed rotted-as-committed pseudo-prototype for VFS_CHECKXP(). It had not
caught up with the changes to avoid storing socket addresses in mbufs,
although the VFS_CHECKEXP() code had to since it was committed 2 years
after those changes.

Fixed formatting in this prototype.

VFS_CHECKEXP.9:
Fix typo.
Fix description.

VFS_FHTOVP.9:
Fix order in which the manpage says the calls should be made.

PR: 18590
Submitted by: Anatoly Vorobey <mellon@pobox.com>

vnode -> mountpoint
reference vfs_check_export
change license to my own, (ok'd by dfr) and remove advert clause.
remove extra Id tags and emacs cruft, this should be a fresh file.

Document VFS changes:

VFS_CHECKEXP.9, now used to check export credentials
VFS_FHTOVP.9, only used for filehandle to vnode, no access checks are done.
VFS.9, inform people of the vfs_std* functions available to avoid
ugly casts to eopnotsup and making of dummy functions to return 0.